Parking assist systems have heretofore been known, in each of which a display device displays an image representing an external environment around a vehicle, and, in a manner superimposing over the image, displays a parking frame image in a target parking position serving as a target position in which the vehicle is to be parked. Techniques for such conventional parking assist systems have been developed in which the parking frame image is displayed so as to eliminate a deviation from an actual target parking position at the time of display before the target parking position is set, and thus, the parking assist is more effectively provided to a user.
Such conventional techniques are described, for example, in Japanese Patent Application Publication No. 2014-166834.
However, although the conventional techniques eliminate the deviation with respect to the displayed parking frame image when the vehicle has moved, deviations in coordinates for actually controlling to guide the vehicle are not eliminated. Hence, to improve the accuracy of the parking assist in the conventional parking assist operation, the parking assist is started on condition that the vehicle is stationary. That is, if the parking assist tries to be started while the vehicle is moving, deviations in coordinates by amounts of the movement can be additionally generated, affecting the accuracy of the parking.